parsons



No. 613,775. Patented NOV. 8, I898. C. A. PARSONS.

SCREW FAN AND PUMP FOB PBOPELLING AIR, 8w.

(Application filed. June 30, 1897.)

2 Sheets-S (No Model.)

I Til/"612607 is co Puoropma. WASN No. 6l3,775.' Patented Nov. 8, I898;

C. A. PARSONS.

SCREW FAN AND PUMP FOR PBDPELLING AIR, 8L0.

(Application filed June so, 1897.) (No Model.) 7 2 Sheets-SheeiZ.

NiTED STATES PATENT tries.

CHARLES ALGERNON PARSONS, OF NEW'CASTLE-UPON-TYNE, ENGLAND.

SCREW FAN AND PUMP FOR PROPELLING AIR, 800.

SIPEOIFICATION forming part of Letters Patent No. 613,775, dated November 8', 1898'.

Application filed June 30, 1897. Serial No. 642,997. (No inoclel.)

To aZZ whom it may concern:

Be in known that I, CHARLES ALGERNON PARSONS, engineer, a citizen of Great Britain, and a resident of Heaton WVorks, NewcastleuponTyne, in the county of North umberland England, have invented certain new and useful Improvements in Screw Fans and Pumps for Propelling Air, Gases, or Liquids, of which the following is a specification.

Myinvention relates to that class of fan or pump in which the air, gas, or liquid is propelled in the desired direction by the action of helices or partial helices fixed upon a rotating boss.

My invention consists in forming the easing in which the propeller works of certain relative dimensions and configuration and in constructing the feed pipe or channel to the pump or fan in the shape of a converging cone or trumpet-mouth, while the exit is arranged in the form of a diverging cone.

\Vhen screw fans or propellers are used for propelling air, gases, or liquids, it is usual to place the propeller within a ring or within the conduit or pipe through which the air, gas, or liquid is required to be forced. I find, however, that the efficiency of the screw-pump is aifected to a very great extent by the form of the ring or conduit in the neighborhood of the propeller and that while a screw-pump Working in a ring or in a conduit of uniform area is comparati vely inefficient, yet by making the tube around the propeller of proper form and proportions a very high degree of efficiency may be reached. I find that the flow of air, gas, or liquid from the blades of the propeller is far from uniform and that it is necessary to prolong the ring around the propeller to a distance of from one to three or more diameters in length in order to mingle the currents. I find that this increases the efficiency by more than thirty per cent. I further find that by making the tube in the form of a gently-diverging cone the efficiency is further increased, and, lastly, I find that the entry to the ring for the best results must be a converging cone or a converging trumpetmouth. By these means I am enabled to 'gentlyaccelerate the air, gas, or liquid in the entry to the screw-propeller up to a suitable velocity for the propeller to work in to the best advantage with a moderate slip ratio and high intrinsic efficiency. On leaving the pro peller the irregular velocity of the several parts of the column mingle and become nearly homogeneous in velocity in the parallel or gently-diverging cone, and their energy is thereby utilized or conserved, while still moving at high velocity. On passing through the diverging cone the kinetic energy is converted into potential energy of pressure.

In practice I find that a gently-diverging cone of three to four diameters nearly doubles the efficiency of the same propeller working in a tube of one diameter only in length. Instead of using a gently-diverging cone throughout behind the propeller I may use a parallel tube of one or two diameters, or more, and add to it a gently-diverging cone. I may also, instead of placing the propeller within the entry to the diverging cone, place it at a short distance in front of or behind the small est section of the casing. I may use this propeller int conjunction with my well-known steam-turbine, or I may drive it by an electromotor or from any other suitable source of power, and I am hereby enabled to move much larger volumes of air, gas, or liquid than is possible with a centrifugal fan or pump of similar dimensions and first cost. I am also hereby enabled to construct a fan or pump with a higher rotational speed than is possible with a centrifugal fan or pump and in many cases to use my steam-turbine for driving the fan or pumps, which would not be otherwise economically possible. In many cases such a fan or pump, for the same reason, is more suitable for working in conjunction with electromotors or any high-speed motor.

The accompanying drawings illustrate two modes of carrying my invention into effect as applied to the propulsion of air and gases.

Figure 1 is a sectional elevation in which my improved propeller driven by one of my steam-turbines is applied to produce suctiondraft in a colliery. Fig. 2 is a plan, partly in section, of my improved propeller as applied for inducing draft in the flue of a boiler or furnace.

Referring to Fig. 1 of the drawings, I arrange a screw-propeller A within a ring-casing B,which is constructed about one diameter in length, and on the top of the draft or uptake 0 I fix a trumpet-shaped or conver= ging pipe D, the smaller diameter being attached to the ring-casing while the larger is fixed to the draft or uptake. Upon the other side of the ring-casing I flX the bottom and smaller end of the funnel E, the said funnel gradually diverging and increasing in diameter to its termination. To actuate the propeller A, 1 preferably arrange one of my wellknown steam-turbines, such as that shown at F, connected to the propeller by the shaft G, though any other high-speed motor may be used. The forced draft caused by the foregoing arrangement is of very high efficiency for the reasons hereinbefore fully described.

Referring now to Fig. 2 of the drawings, wherein an application of my invention to the forcing of air or gases is illustrated, I arrange a screw-propellerH upon a shaft Lactaated by one of my steam-turbines revolving within a ring-casing K and having the air or gas supply passage L gently converging and therefore decreasing in diameter from K to K where it meets the ring-casing, while the exit M gently diverges from K to K, and therefore increases in diameter from the ringcasing to the point of delivery K (Shown on the drawings.) By this application of my invention high efficiency in forcing air or gases is secured and for the reasons hereinbefore fully described. It is to be clearly understood that this arrangement of converging supply-passages and diverging delivery-passages leading to and from a parallel or other casing containing a screw-propeller driven at high velocity by a steam-turbine or other rapidly-rotating motor is the main feature of my invention, while it is obvious that it is capable of application for use in producing forced or induced draft on board ship, and, in fact, that it may be universally applied.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is

In combination in an air-forcing device, the propeller, the casing inclosing the same of cylindrical form and uniform crosssection, the converging air-supply casing on one side of the parallel cylindrical casing and the diverging discharge-casing on the other side of the said cylindrical casing, substantially as described.

In witness whereof I have hereunto set my hand in presence of two Witnesses CHARLES ALGERNON PARSONS;

Vitnesses:

WILLIAM MENZIES JOHNSTON, EDWARD OsWALD CHARLTON. 

